In reality, a mixture of cumulus and stratocumulus clouds with the cumulus clouds in the background flattening out due to cumulus clouds above. The wave-like structure of some clouds (grey cloud on the photo`s right hand side) is actually stratocumulus. This mixture of cloud formation is more than one type of cloud whose common denominator was a low pressure system (seen as solid black line) around Southern Italy on the 4th thumbnail. The differences in cloud formation was due to stable and unstable layers within the atmosphere as the air was rising due to low pressure and due to nearby clouds. The air profile could be seen on the third thumbnail. This mass of cloud did produce a heavy rain shower to the SE of Malta out at sea which quickly decayed later as indicated by the 5th thumbnail. The first and second thumbnails are altocumulus perlucidus and widespread cirrus respectively that preceded the arrival of isolated rain showers more akin to a passing frontal system. However, no fronts were observed and could have been the effect of former thunderstorm clouds and approaching of the trough.